Thermador Star-Sapphire Dishwasher: Features & Common Issues

The Thermador Star-Sapphire series (DWHD860WFP, DWHD870WFP, DWHD770WFP) sits at the top of Thermador's dishwasher lineup, featuring Zeolite mineral drying technology, a 3rd rack with dedicated spray arm, and the PowerBoost option that cuts cycle time by up to 50%. As factory-trained technicians who service these units across the Bay Area, here's what owners should know.

Key Features

Zeolite Drying: Instead of a traditional heating element, Star-Sapphire models use zeolite minerals that absorb moisture and release heat. This is more energy-efficient and gentler on plastics, but it adds complexity. The zeolite container (part 00702456) is a sealed unit that should last the lifetime of the dishwasher, but the fan that circulates air through it can fail.

PowerBoost: An option that increases water pressure to the lower spray arm, cutting heavy-soil cycle time from 2.5 hours to under 90 minutes. We see the most service calls on units where PowerBoost is used daily — the increased pressure stresses the circulation pump seals over time.

3rd Rack with Spray Arm: The full-width 3rd rack has its own dedicated spray arm and water supply. The hose routing is complex, and we've seen leaks develop where the hose passes through the rear wall of the tub.

Error Code E9 — Heating System

E9 indicates the Zeolite drying system is not reaching target temperature, or the NTC sensor is reading out of range. Because the Star-Sapphire doesn't use a traditional heating element, this error often points to:

• Failed zeolite air circulation fan
• NTC temperature sensor drift
• Control board relay failure
• Blocked air channel (rare, but seen in homes with hard water scale)

Error Code E15 — Water Leak

Like Bosch dishwashers (Thermador is part of the BSH group), the Star-Sapphire uses an AquaStop system. E15 means water has been detected in the base pan. On Star-Sapphire models, we most often trace this to:

• 3rd rack spray arm hose connection loosening from vibration
• Circulation pump seal failure (exacerbated by frequent PowerBoost use)
• Over-sudsing from incorrect detergent
• Door seal deformation from heat exposure

Maintenance Recommendations

1. Use only Finish Quantum or Cascade Platinum pods — regular detergent causes over-sudsing
2. Run the "Machine Care" cycle monthly with dishwasher cleaner
3. Clean the filter assembly weekly (located under the bottom rack)
4. Check the door seal monthly for food debris or damage
5. Avoid using PowerBoost on every cycle — reserve it for heavily soiled loads